Both heavy and naughty are adjectives because they are used to describe nouns. Dependence is a noun because it is a state of being.

Strength, here, means the number of people in the class.

 Swimmimg is an uncountable noun and is the correct answer. Bumpy and fluff do not fit the context.

All the other options are adjectives. Technology is a noun. So, it is the correct answer.

A question is answered, a problem is solved, a subject is studied and, a part is usually played, so the correct answer is question.

The correct idiom is 'fallen in love'. Hence, option 3 is correct.

Curse cannot be used with give me, sweet (singular) cannot be used with some. Sweets is the correct answer.

Question is the correct answer. 

Honey is eaten. Children love to drink milk and not water, so milk is the correct answer.

 Lady is the correct answer. It is a countable noun. If there was a comma after 'this', then darling and love could have been used.

 Use is the correct answer. Usage and useful cannot be used before 'book'. Foundation is used for structures, ideas, organisations, etc.

Disposition refers to a person's temperament. It is the correct answer.

Visit is used with palace. Way and project cannot be used here. Place is the correct answer.

Nature is always used in a singular form. Night and nurse are in a singular form, so cannot be used with 'are'. Neighbours is the correct answer.

 'Honesty is the best policy' is an idiom. Honesty is the correct answer.